Mosquitoes are small flying insects mostly known to humans because of their bites and the diseases they transmit. Although there are several species of mosquitoes, their bio-ecology is somewhat similar in many aspects. Some mosquito species are domestic or peridomestics, other species remains in the wild where they parasite wild animals such as monkeys, rodents etc…
Mosquitoes can develop and breed in different kind of environments ranging from rain forest to high mountains, arctic tundra, salt marshes and coastal zones. It is only in Antarctica that mosquito cannot be found on this planet. Human alteration of the environment is the major factor contribute to the development and establishment of mosquito population in urban and rural environment.
Mosquitoes are holometabolous insects, which means that they have complete metamorphosis. Mosquitoes undergo 4 different stages during their life including, eggs, larvae, pupae ad adults (Goma, 1966). The first 3 stages are aquatics or somewhat connected with water.
Depending on the genus or species, eggs may be laid on large body of standing water, such as pools or tree holes. This is typically the case of Anopheles and Culex mosquitoes. Aedes mosquitoes, on the other hand, lay their eggs on on damp surfaces, tree holes or man-made containers where there are likely to be flooded by water. Aedes lay their eggs singly, while Anopheles and Culex lay their eggs in a clutch or raft.
Mosquito larvae undergo 4 distinct sub-stages called instars. The first instar correspond to the newly hatched larvae the other 3 instars are determined by 3 successive molting. These events happen in 7 days in generally although there are variations depending on the species and environmental conditions. Mosquito larvae are commonly known as wigglers.
Mosquito larvae are water filter feeder. They use their mouthparts to filter organic matter as food source. They may also feed on microorganism like bacteria and yeast. The amount of time that mosquito stay as larvae depend on the species and temperature.
In the laboratory, we have noticed that temperature accelerate the rate of development of many insects including mosquitoes. Aedes larvae breathe by means of a siphon held above the water surface while the rest of the body hangs vertically.
Mosquito pupae are unusual as compared to pupae of most insect. They do not feed as most insect larvae do, however they move. In most case insect pupae do not move they are fixed at one place to finish their development. The pupal stage lasting 2 to 3 days depending on the environmental conditions. The size of the pupae depend on the amount food they consume during larval stage.
Adults of all mosquitoes are exclusively terrestrial. Adult mosquitoes usually live from 2 to 4 weeks depending on the species and environmental conditions. Adult females are usually larger than males.